1. Field of the Invention
The present invention relates generally to rotary engines and, more particularly, to a sliding blade rotary engine.
2. Description of the Prior Art
Rotary engines have been known which convert steam or which convert the pressurized gases resulting from the ignition of a combustible fuel into a mechanical output torque. For example, U.S. Pat. Nos. 192,547 to Vaile and 44,247 to Wood et al. disclose a rotary engine comprising a cylindrical rotor secured to a drive shaft and concentrically mounted inside a stationary cylinder. A plurality of chamber separators extend inwardly from the stationary cylinder to bear against the periphery of the rotor to form a plurality of pressure chambers. Sliding blades carried in spaced radial slots in the rotor extend into the pressure chambers where they are acted upon by the pressurized motive fluid to turn the rotor and the drive shaft.
The rotary engines shown in the Wood and Vaile patents, which may be termed sliding blade type engines, are quite complicated and are made from numerous components, thereby increasing the cost of the engines. For example, both Wood and Vaile provide separate valves for each of the pressure chambers to separately control the pressure inlet and exhaust outlet in each chamber. In addition, the inlet and exhaust ports of these valves are connected to supply passages located in an outer jacket surrounding the stationary cylinder. The outer jacket increases both the size and weight of the engine. Finally, both Wood and Vaile project the sliding rotor blades into a steam tight fit with the stationary cylinder thereby imposing a great deal of friction and wear on the blades. In this regard, U.S. Pat. No. 1,488,729 to Ballay discloses a method for limiting the outward movement of sliding rotor blades in a rotary pump to prevent friction with the stationary cylinder, but this is accomplished only through the use of movement controlling slots in flanges attached to the sides of the rotor, the flanges again increasing the size and complexity of the pump.
Another problem presented by sliding blade rotary engines is the need to transfer the blades during movement of the rotor below the stationary abutments used to form the pressure chambers. Most prior art devices for accomplishing this are either unduly complicated and expensive or present problems of extreme wear on the blades. For example, the Wood and Vaile patents use fixed cams on the engine housing to coact with pins extending from the blades to reciprocate the blades into and out of their slots in the rotor. Such an unyielding relationship between the components quickly wears the pins on the blades, thus necessitating frequent blade replacement and giving rise to increased operational costs.
The Ballay patent and U.S. Pat. No. 1,530,307 to Dawson disclose a slotted rotatable ring and a plurality of rotatable star wheels, respectively, for reciprocating the blades in a rotary pump or engine. These devices probably cause somewhat less wear on the blades than engagement with a fixed cam. However, Ballay's ring must be mounted eccentrically with regard to the rotor to accomplish reciprocation of the blades, thereby increasing the size of his engine. Dawson's star wheels are only effective to extend, not to retract, the blades, and are driven in a timed relationship by the drive shaft to extend the blades, thereby diverting part of the power produced by the engine just to operate the blades.